Heat losses assessment of an UHT-LHTPV system coupled with concentrated solar power

This work assesses the energy performance of a FeSiB-based latent heat thermophotovoltaic (LHTPV) system coupled with beam-down concentrated solar power (CSP) optics targeting for ultra-high temperature energy storage and conversion (~1250 oC). The basic unit is a compact device consisting of a charging (CSP), a storage (LHTES) and a heat-topower conversion (TPV) system that can be replicated to form the CSP-LHTPV system, though a bottom-up approach. At such unprecedented temperatures, critical operating parameters, including excess heat losses arising mainly through the LHTES system walls and solar aperture, should be determined within all four possible operating modes, i.e. charging, discharging, simultaneous charging/discharging, and storage modes. A validated transient three-dimensional computational fluid dynamics (CFD) model is applied in ANSYS Fluent v22.R2 platform to give insights on the system thermal performance and prove its operability under various insulating methods (with thermal resistances within ~0.1-0.85 m2K/W). Based on the thermal analysis, the proposed concept meets several desirable key performance indicators, including solar concentration flux of > 1000 suns, input power within 10-20 kWth, and charging/ discharging period of 1-2 h / 4-8 h, paving, thus, the way as a competitive highly-efficient renewable energy technology.